Commit | Line | Data |
---|---|---|
237fead6 MH |
1 | /** |
2 | * eCryptfs: Linux filesystem encryption layer | |
3 | * | |
4 | * Copyright (C) 1997-2004 Erez Zadok | |
5 | * Copyright (C) 2001-2004 Stony Brook University | |
dd2a3b7a | 6 | * Copyright (C) 2004-2007 International Business Machines Corp. |
237fead6 MH |
7 | * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
8 | * Michael C. Thompson <mcthomps@us.ibm.com> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License as | |
12 | * published by the Free Software Foundation; either version 2 of the | |
13 | * License, or (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, but | |
16 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | * General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with this program; if not, write to the Free Software | |
22 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA | |
23 | * 02111-1307, USA. | |
24 | */ | |
25 | ||
26 | #include <linux/fs.h> | |
27 | #include <linux/mount.h> | |
28 | #include <linux/pagemap.h> | |
29 | #include <linux/random.h> | |
30 | #include <linux/compiler.h> | |
31 | #include <linux/key.h> | |
32 | #include <linux/namei.h> | |
33 | #include <linux/crypto.h> | |
34 | #include <linux/file.h> | |
35 | #include <linux/scatterlist.h> | |
5a0e3ad6 | 36 | #include <linux/slab.h> |
29335c6a | 37 | #include <asm/unaligned.h> |
237fead6 MH |
38 | #include "ecryptfs_kernel.h" |
39 | ||
00a69940 TH |
40 | #define DECRYPT 0 |
41 | #define ENCRYPT 1 | |
237fead6 MH |
42 | |
43 | /** | |
44 | * ecryptfs_to_hex | |
45 | * @dst: Buffer to take hex character representation of contents of | |
46 | * src; must be at least of size (src_size * 2) | |
47 | * @src: Buffer to be converted to a hex string respresentation | |
48 | * @src_size: number of bytes to convert | |
49 | */ | |
50 | void ecryptfs_to_hex(char *dst, char *src, size_t src_size) | |
51 | { | |
52 | int x; | |
53 | ||
54 | for (x = 0; x < src_size; x++) | |
55 | sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]); | |
56 | } | |
57 | ||
58 | /** | |
59 | * ecryptfs_from_hex | |
60 | * @dst: Buffer to take the bytes from src hex; must be at least of | |
61 | * size (src_size / 2) | |
62 | * @src: Buffer to be converted from a hex string respresentation to raw value | |
63 | * @dst_size: size of dst buffer, or number of hex characters pairs to convert | |
64 | */ | |
65 | void ecryptfs_from_hex(char *dst, char *src, int dst_size) | |
66 | { | |
67 | int x; | |
68 | char tmp[3] = { 0, }; | |
69 | ||
70 | for (x = 0; x < dst_size; x++) { | |
71 | tmp[0] = src[x * 2]; | |
72 | tmp[1] = src[x * 2 + 1]; | |
73 | dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16); | |
74 | } | |
75 | } | |
76 | ||
77 | /** | |
78 | * ecryptfs_calculate_md5 - calculates the md5 of @src | |
79 | * @dst: Pointer to 16 bytes of allocated memory | |
80 | * @crypt_stat: Pointer to crypt_stat struct for the current inode | |
81 | * @src: Data to be md5'd | |
82 | * @len: Length of @src | |
83 | * | |
84 | * Uses the allocated crypto context that crypt_stat references to | |
85 | * generate the MD5 sum of the contents of src. | |
86 | */ | |
87 | static int ecryptfs_calculate_md5(char *dst, | |
88 | struct ecryptfs_crypt_stat *crypt_stat, | |
89 | char *src, int len) | |
90 | { | |
237fead6 | 91 | struct scatterlist sg; |
565d9724 MH |
92 | struct hash_desc desc = { |
93 | .tfm = crypt_stat->hash_tfm, | |
94 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP | |
95 | }; | |
96 | int rc = 0; | |
237fead6 | 97 | |
565d9724 | 98 | mutex_lock(&crypt_stat->cs_hash_tfm_mutex); |
237fead6 | 99 | sg_init_one(&sg, (u8 *)src, len); |
565d9724 MH |
100 | if (!desc.tfm) { |
101 | desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0, | |
102 | CRYPTO_ALG_ASYNC); | |
103 | if (IS_ERR(desc.tfm)) { | |
104 | rc = PTR_ERR(desc.tfm); | |
237fead6 | 105 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
565d9724 MH |
106 | "allocate crypto context; rc = [%d]\n", |
107 | rc); | |
237fead6 MH |
108 | goto out; |
109 | } | |
565d9724 | 110 | crypt_stat->hash_tfm = desc.tfm; |
237fead6 | 111 | } |
8a29f2b0 MH |
112 | rc = crypto_hash_init(&desc); |
113 | if (rc) { | |
114 | printk(KERN_ERR | |
115 | "%s: Error initializing crypto hash; rc = [%d]\n", | |
18d1dbf1 | 116 | __func__, rc); |
8a29f2b0 MH |
117 | goto out; |
118 | } | |
119 | rc = crypto_hash_update(&desc, &sg, len); | |
120 | if (rc) { | |
121 | printk(KERN_ERR | |
122 | "%s: Error updating crypto hash; rc = [%d]\n", | |
18d1dbf1 | 123 | __func__, rc); |
8a29f2b0 MH |
124 | goto out; |
125 | } | |
126 | rc = crypto_hash_final(&desc, dst); | |
127 | if (rc) { | |
128 | printk(KERN_ERR | |
129 | "%s: Error finalizing crypto hash; rc = [%d]\n", | |
18d1dbf1 | 130 | __func__, rc); |
8a29f2b0 MH |
131 | goto out; |
132 | } | |
237fead6 | 133 | out: |
8a29f2b0 | 134 | mutex_unlock(&crypt_stat->cs_hash_tfm_mutex); |
237fead6 MH |
135 | return rc; |
136 | } | |
137 | ||
cd9d67df MH |
138 | static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
139 | char *cipher_name, | |
140 | char *chaining_modifier) | |
8bba066f MH |
141 | { |
142 | int cipher_name_len = strlen(cipher_name); | |
143 | int chaining_modifier_len = strlen(chaining_modifier); | |
144 | int algified_name_len; | |
145 | int rc; | |
146 | ||
147 | algified_name_len = (chaining_modifier_len + cipher_name_len + 3); | |
148 | (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); | |
7bd473fc | 149 | if (!(*algified_name)) { |
8bba066f MH |
150 | rc = -ENOMEM; |
151 | goto out; | |
152 | } | |
153 | snprintf((*algified_name), algified_name_len, "%s(%s)", | |
154 | chaining_modifier, cipher_name); | |
155 | rc = 0; | |
156 | out: | |
157 | return rc; | |
158 | } | |
159 | ||
237fead6 MH |
160 | /** |
161 | * ecryptfs_derive_iv | |
162 | * @iv: destination for the derived iv vale | |
163 | * @crypt_stat: Pointer to crypt_stat struct for the current inode | |
d6a13c17 | 164 | * @offset: Offset of the extent whose IV we are to derive |
237fead6 MH |
165 | * |
166 | * Generate the initialization vector from the given root IV and page | |
167 | * offset. | |
168 | * | |
169 | * Returns zero on success; non-zero on error. | |
170 | */ | |
a34f60f7 MH |
171 | int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, |
172 | loff_t offset) | |
237fead6 MH |
173 | { |
174 | int rc = 0; | |
175 | char dst[MD5_DIGEST_SIZE]; | |
176 | char src[ECRYPTFS_MAX_IV_BYTES + 16]; | |
177 | ||
178 | if (unlikely(ecryptfs_verbosity > 0)) { | |
179 | ecryptfs_printk(KERN_DEBUG, "root iv:\n"); | |
180 | ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); | |
181 | } | |
182 | /* TODO: It is probably secure to just cast the least | |
183 | * significant bits of the root IV into an unsigned long and | |
184 | * add the offset to that rather than go through all this | |
185 | * hashing business. -Halcrow */ | |
186 | memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); | |
187 | memset((src + crypt_stat->iv_bytes), 0, 16); | |
d6a13c17 | 188 | snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset); |
237fead6 MH |
189 | if (unlikely(ecryptfs_verbosity > 0)) { |
190 | ecryptfs_printk(KERN_DEBUG, "source:\n"); | |
191 | ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); | |
192 | } | |
193 | rc = ecryptfs_calculate_md5(dst, crypt_stat, src, | |
194 | (crypt_stat->iv_bytes + 16)); | |
195 | if (rc) { | |
196 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
197 | "MD5 while generating IV for a page\n"); | |
198 | goto out; | |
199 | } | |
200 | memcpy(iv, dst, crypt_stat->iv_bytes); | |
201 | if (unlikely(ecryptfs_verbosity > 0)) { | |
202 | ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); | |
203 | ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); | |
204 | } | |
205 | out: | |
206 | return rc; | |
207 | } | |
208 | ||
209 | /** | |
210 | * ecryptfs_init_crypt_stat | |
211 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. | |
212 | * | |
213 | * Initialize the crypt_stat structure. | |
214 | */ | |
215 | void | |
216 | ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) | |
217 | { | |
218 | memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); | |
f4aad16a MH |
219 | INIT_LIST_HEAD(&crypt_stat->keysig_list); |
220 | mutex_init(&crypt_stat->keysig_list_mutex); | |
237fead6 MH |
221 | mutex_init(&crypt_stat->cs_mutex); |
222 | mutex_init(&crypt_stat->cs_tfm_mutex); | |
565d9724 | 223 | mutex_init(&crypt_stat->cs_hash_tfm_mutex); |
e2bd99ec | 224 | crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED; |
237fead6 MH |
225 | } |
226 | ||
227 | /** | |
fcd12835 | 228 | * ecryptfs_destroy_crypt_stat |
237fead6 MH |
229 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
230 | * | |
231 | * Releases all memory associated with a crypt_stat struct. | |
232 | */ | |
fcd12835 | 233 | void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
237fead6 | 234 | { |
f4aad16a MH |
235 | struct ecryptfs_key_sig *key_sig, *key_sig_tmp; |
236 | ||
237fead6 | 237 | if (crypt_stat->tfm) |
4dfea4f0 | 238 | crypto_free_ablkcipher(crypt_stat->tfm); |
565d9724 MH |
239 | if (crypt_stat->hash_tfm) |
240 | crypto_free_hash(crypt_stat->hash_tfm); | |
f4aad16a MH |
241 | list_for_each_entry_safe(key_sig, key_sig_tmp, |
242 | &crypt_stat->keysig_list, crypt_stat_list) { | |
243 | list_del(&key_sig->crypt_stat_list); | |
244 | kmem_cache_free(ecryptfs_key_sig_cache, key_sig); | |
245 | } | |
237fead6 MH |
246 | memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
247 | } | |
248 | ||
fcd12835 | 249 | void ecryptfs_destroy_mount_crypt_stat( |
237fead6 MH |
250 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
251 | { | |
f4aad16a MH |
252 | struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp; |
253 | ||
254 | if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED)) | |
255 | return; | |
256 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
257 | list_for_each_entry_safe(auth_tok, auth_tok_tmp, | |
258 | &mount_crypt_stat->global_auth_tok_list, | |
259 | mount_crypt_stat_list) { | |
260 | list_del(&auth_tok->mount_crypt_stat_list); | |
f4aad16a MH |
261 | if (auth_tok->global_auth_tok_key |
262 | && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID)) | |
263 | key_put(auth_tok->global_auth_tok_key); | |
264 | kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok); | |
265 | } | |
266 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
237fead6 MH |
267 | memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
268 | } | |
269 | ||
270 | /** | |
271 | * virt_to_scatterlist | |
272 | * @addr: Virtual address | |
273 | * @size: Size of data; should be an even multiple of the block size | |
274 | * @sg: Pointer to scatterlist array; set to NULL to obtain only | |
275 | * the number of scatterlist structs required in array | |
276 | * @sg_size: Max array size | |
277 | * | |
278 | * Fills in a scatterlist array with page references for a passed | |
279 | * virtual address. | |
280 | * | |
281 | * Returns the number of scatterlist structs in array used | |
282 | */ | |
283 | int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, | |
284 | int sg_size) | |
285 | { | |
286 | int i = 0; | |
287 | struct page *pg; | |
288 | int offset; | |
289 | int remainder_of_page; | |
290 | ||
68e3f5dd HX |
291 | sg_init_table(sg, sg_size); |
292 | ||
237fead6 MH |
293 | while (size > 0 && i < sg_size) { |
294 | pg = virt_to_page(addr); | |
295 | offset = offset_in_page(addr); | |
a07c48ad | 296 | sg_set_page(&sg[i], pg, 0, offset); |
237fead6 MH |
297 | remainder_of_page = PAGE_CACHE_SIZE - offset; |
298 | if (size >= remainder_of_page) { | |
a07c48ad | 299 | sg[i].length = remainder_of_page; |
237fead6 MH |
300 | addr += remainder_of_page; |
301 | size -= remainder_of_page; | |
302 | } else { | |
a07c48ad | 303 | sg[i].length = size; |
237fead6 MH |
304 | addr += size; |
305 | size = 0; | |
306 | } | |
307 | i++; | |
308 | } | |
309 | if (size > 0) | |
310 | return -ENOMEM; | |
311 | return i; | |
312 | } | |
313 | ||
4dfea4f0 TH |
314 | struct extent_crypt_result { |
315 | struct completion completion; | |
316 | int rc; | |
317 | }; | |
318 | ||
319 | static void extent_crypt_complete(struct crypto_async_request *req, int rc) | |
320 | { | |
321 | struct extent_crypt_result *ecr = req->data; | |
322 | ||
323 | if (rc == -EINPROGRESS) | |
324 | return; | |
325 | ||
326 | ecr->rc = rc; | |
327 | complete(&ecr->completion); | |
328 | } | |
329 | ||
237fead6 | 330 | /** |
00a69940 | 331 | * crypt_scatterlist |
237fead6 | 332 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
0df5ed65 | 333 | * @dst_sg: Destination of the data after performing the crypto operation |
00a69940 TH |
334 | * @src_sg: Data to be encrypted or decrypted |
335 | * @size: Length of data | |
336 | * @iv: IV to use | |
337 | * @op: ENCRYPT or DECRYPT to indicate the desired operation | |
237fead6 | 338 | * |
00a69940 | 339 | * Returns the number of bytes encrypted or decrypted; negative value on error |
237fead6 | 340 | */ |
00a69940 | 341 | static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
0df5ed65 | 342 | struct scatterlist *dst_sg, |
00a69940 TH |
343 | struct scatterlist *src_sg, int size, |
344 | unsigned char *iv, int op) | |
237fead6 | 345 | { |
4dfea4f0 TH |
346 | struct ablkcipher_request *req = NULL; |
347 | struct extent_crypt_result ecr; | |
237fead6 MH |
348 | int rc = 0; |
349 | ||
350 | BUG_ON(!crypt_stat || !crypt_stat->tfm | |
e2bd99ec | 351 | || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)); |
237fead6 | 352 | if (unlikely(ecryptfs_verbosity > 0)) { |
f24b3887 | 353 | ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n", |
237fead6 MH |
354 | crypt_stat->key_size); |
355 | ecryptfs_dump_hex(crypt_stat->key, | |
356 | crypt_stat->key_size); | |
357 | } | |
4dfea4f0 TH |
358 | |
359 | init_completion(&ecr.completion); | |
360 | ||
237fead6 | 361 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
4dfea4f0 TH |
362 | req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS); |
363 | if (!req) { | |
237fead6 | 364 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
4dfea4f0 | 365 | rc = -ENOMEM; |
237fead6 MH |
366 | goto out; |
367 | } | |
4dfea4f0 TH |
368 | |
369 | ablkcipher_request_set_callback(req, | |
370 | CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, | |
371 | extent_crypt_complete, &ecr); | |
372 | /* Consider doing this once, when the file is opened */ | |
373 | if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) { | |
374 | rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key, | |
375 | crypt_stat->key_size); | |
376 | if (rc) { | |
377 | ecryptfs_printk(KERN_ERR, | |
378 | "Error setting key; rc = [%d]\n", | |
379 | rc); | |
380 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
381 | rc = -EINVAL; | |
382 | goto out; | |
383 | } | |
384 | crypt_stat->flags |= ECRYPTFS_KEY_SET; | |
385 | } | |
237fead6 | 386 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
0df5ed65 | 387 | ablkcipher_request_set_crypt(req, src_sg, dst_sg, size, iv); |
00a69940 TH |
388 | rc = op == ENCRYPT ? crypto_ablkcipher_encrypt(req) : |
389 | crypto_ablkcipher_decrypt(req); | |
4dfea4f0 TH |
390 | if (rc == -EINPROGRESS || rc == -EBUSY) { |
391 | struct extent_crypt_result *ecr = req->base.data; | |
392 | ||
393 | wait_for_completion(&ecr->completion); | |
394 | rc = ecr->rc; | |
16735d02 | 395 | reinit_completion(&ecr->completion); |
4dfea4f0 | 396 | } |
237fead6 | 397 | out: |
4dfea4f0 | 398 | ablkcipher_request_free(req); |
237fead6 MH |
399 | return rc; |
400 | } | |
401 | ||
0216f7f7 | 402 | /** |
24d15266 | 403 | * lower_offset_for_page |
0216f7f7 MH |
404 | * |
405 | * Convert an eCryptfs page index into a lower byte offset | |
406 | */ | |
24d15266 TH |
407 | static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat, |
408 | struct page *page) | |
0216f7f7 | 409 | { |
24d15266 | 410 | return ecryptfs_lower_header_size(crypt_stat) + |
43b7c6c6 | 411 | ((loff_t)page->index << PAGE_CACHE_SHIFT); |
0216f7f7 MH |
412 | } |
413 | ||
414 | /** | |
d78de618 | 415 | * crypt_extent |
0216f7f7 MH |
416 | * @crypt_stat: crypt_stat containing cryptographic context for the |
417 | * encryption operation | |
0df5ed65 | 418 | * @dst_page: The page to write the result into |
d78de618 | 419 | * @src_page: The page to read from |
0216f7f7 | 420 | * @extent_offset: Page extent offset for use in generating IV |
d78de618 | 421 | * @op: ENCRYPT or DECRYPT to indicate the desired operation |
0216f7f7 | 422 | * |
d78de618 | 423 | * Encrypts or decrypts one extent of data. |
0216f7f7 MH |
424 | * |
425 | * Return zero on success; non-zero otherwise | |
426 | */ | |
0df5ed65 TH |
427 | static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat, |
428 | struct page *dst_page, | |
d78de618 TH |
429 | struct page *src_page, |
430 | unsigned long extent_offset, int op) | |
0216f7f7 | 431 | { |
d78de618 | 432 | pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index; |
d6a13c17 | 433 | loff_t extent_base; |
0216f7f7 | 434 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
406c93df TH |
435 | struct scatterlist src_sg, dst_sg; |
436 | size_t extent_size = crypt_stat->extent_size; | |
0216f7f7 MH |
437 | int rc; |
438 | ||
406c93df | 439 | extent_base = (((loff_t)page_index) * (PAGE_CACHE_SIZE / extent_size)); |
0216f7f7 MH |
440 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
441 | (extent_base + extent_offset)); | |
442 | if (rc) { | |
888d57bb JP |
443 | ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for " |
444 | "extent [0x%.16llx]; rc = [%d]\n", | |
445 | (unsigned long long)(extent_base + extent_offset), rc); | |
0216f7f7 MH |
446 | goto out; |
447 | } | |
406c93df TH |
448 | |
449 | sg_init_table(&src_sg, 1); | |
450 | sg_init_table(&dst_sg, 1); | |
451 | ||
452 | sg_set_page(&src_sg, src_page, extent_size, | |
453 | extent_offset * extent_size); | |
454 | sg_set_page(&dst_sg, dst_page, extent_size, | |
455 | extent_offset * extent_size); | |
456 | ||
457 | rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size, | |
458 | extent_iv, op); | |
0216f7f7 | 459 | if (rc < 0) { |
d78de618 TH |
460 | printk(KERN_ERR "%s: Error attempting to crypt page with " |
461 | "page_index = [%ld], extent_offset = [%ld]; " | |
462 | "rc = [%d]\n", __func__, page_index, extent_offset, rc); | |
0216f7f7 MH |
463 | goto out; |
464 | } | |
465 | rc = 0; | |
0216f7f7 MH |
466 | out: |
467 | return rc; | |
468 | } | |
469 | ||
237fead6 MH |
470 | /** |
471 | * ecryptfs_encrypt_page | |
0216f7f7 MH |
472 | * @page: Page mapped from the eCryptfs inode for the file; contains |
473 | * decrypted content that needs to be encrypted (to a temporary | |
474 | * page; not in place) and written out to the lower file | |
237fead6 MH |
475 | * |
476 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note | |
477 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
478 | * if the file was created on a machine with an 8K page size | |
479 | * (resulting in an 8K header), and then the file is copied onto a | |
480 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
481 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
482 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
483 | * | |
237fead6 MH |
484 | * Returns zero on success; negative on error |
485 | */ | |
0216f7f7 | 486 | int ecryptfs_encrypt_page(struct page *page) |
237fead6 | 487 | { |
0216f7f7 | 488 | struct inode *ecryptfs_inode; |
237fead6 | 489 | struct ecryptfs_crypt_stat *crypt_stat; |
7fcba054 ES |
490 | char *enc_extent_virt; |
491 | struct page *enc_extent_page = NULL; | |
0216f7f7 | 492 | loff_t extent_offset; |
0f896176 | 493 | loff_t lower_offset; |
237fead6 | 494 | int rc = 0; |
0216f7f7 MH |
495 | |
496 | ecryptfs_inode = page->mapping->host; | |
497 | crypt_stat = | |
498 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 499 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
7fcba054 ES |
500 | enc_extent_page = alloc_page(GFP_USER); |
501 | if (!enc_extent_page) { | |
0216f7f7 MH |
502 | rc = -ENOMEM; |
503 | ecryptfs_printk(KERN_ERR, "Error allocating memory for " | |
504 | "encrypted extent\n"); | |
505 | goto out; | |
506 | } | |
0f896176 | 507 | |
0216f7f7 MH |
508 | for (extent_offset = 0; |
509 | extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); | |
510 | extent_offset++) { | |
0df5ed65 | 511 | rc = crypt_extent(crypt_stat, enc_extent_page, page, |
d78de618 | 512 | extent_offset, ENCRYPT); |
237fead6 | 513 | if (rc) { |
0216f7f7 | 514 | printk(KERN_ERR "%s: Error encrypting extent; " |
18d1dbf1 | 515 | "rc = [%d]\n", __func__, rc); |
237fead6 MH |
516 | goto out; |
517 | } | |
7fcba054 | 518 | } |
0216f7f7 | 519 | |
24d15266 | 520 | lower_offset = lower_offset_for_page(crypt_stat, page); |
0f896176 TH |
521 | enc_extent_virt = kmap(enc_extent_page); |
522 | rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset, | |
523 | PAGE_CACHE_SIZE); | |
524 | kunmap(enc_extent_page); | |
0216f7f7 | 525 | if (rc < 0) { |
0f896176 TH |
526 | ecryptfs_printk(KERN_ERR, |
527 | "Error attempting to write lower page; rc = [%d]\n", | |
528 | rc); | |
0216f7f7 MH |
529 | goto out; |
530 | } | |
531 | rc = 0; | |
237fead6 | 532 | out: |
7fcba054 | 533 | if (enc_extent_page) { |
7fcba054 ES |
534 | __free_page(enc_extent_page); |
535 | } | |
237fead6 MH |
536 | return rc; |
537 | } | |
538 | ||
539 | /** | |
540 | * ecryptfs_decrypt_page | |
0216f7f7 MH |
541 | * @page: Page mapped from the eCryptfs inode for the file; data read |
542 | * and decrypted from the lower file will be written into this | |
543 | * page | |
237fead6 MH |
544 | * |
545 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note | |
546 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
547 | * if the file was created on a machine with an 8K page size | |
548 | * (resulting in an 8K header), and then the file is copied onto a | |
549 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
550 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
551 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
552 | * | |
553 | * Returns zero on success; negative on error | |
554 | */ | |
0216f7f7 | 555 | int ecryptfs_decrypt_page(struct page *page) |
237fead6 | 556 | { |
0216f7f7 | 557 | struct inode *ecryptfs_inode; |
237fead6 | 558 | struct ecryptfs_crypt_stat *crypt_stat; |
9c6043f4 | 559 | char *page_virt; |
0216f7f7 | 560 | unsigned long extent_offset; |
0f896176 | 561 | loff_t lower_offset; |
237fead6 | 562 | int rc = 0; |
237fead6 | 563 | |
0216f7f7 MH |
564 | ecryptfs_inode = page->mapping->host; |
565 | crypt_stat = | |
566 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 567 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
0f896176 | 568 | |
24d15266 | 569 | lower_offset = lower_offset_for_page(crypt_stat, page); |
9c6043f4 TH |
570 | page_virt = kmap(page); |
571 | rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_CACHE_SIZE, | |
0f896176 | 572 | ecryptfs_inode); |
9c6043f4 | 573 | kunmap(page); |
0f896176 TH |
574 | if (rc < 0) { |
575 | ecryptfs_printk(KERN_ERR, | |
576 | "Error attempting to read lower page; rc = [%d]\n", | |
577 | rc); | |
16a72c45 | 578 | goto out; |
237fead6 | 579 | } |
0f896176 | 580 | |
0216f7f7 MH |
581 | for (extent_offset = 0; |
582 | extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); | |
583 | extent_offset++) { | |
0df5ed65 | 584 | rc = crypt_extent(crypt_stat, page, page, |
d78de618 | 585 | extent_offset, DECRYPT); |
0216f7f7 MH |
586 | if (rc) { |
587 | printk(KERN_ERR "%s: Error encrypting extent; " | |
18d1dbf1 | 588 | "rc = [%d]\n", __func__, rc); |
16a72c45 | 589 | goto out; |
237fead6 | 590 | } |
237fead6 MH |
591 | } |
592 | out: | |
237fead6 | 593 | return rc; |
237fead6 MH |
594 | } |
595 | ||
596 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 | |
597 | ||
598 | /** | |
599 | * ecryptfs_init_crypt_ctx | |
421f91d2 | 600 | * @crypt_stat: Uninitialized crypt stats structure |
237fead6 MH |
601 | * |
602 | * Initialize the crypto context. | |
603 | * | |
604 | * TODO: Performance: Keep a cache of initialized cipher contexts; | |
605 | * only init if needed | |
606 | */ | |
607 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) | |
608 | { | |
8bba066f | 609 | char *full_alg_name; |
237fead6 MH |
610 | int rc = -EINVAL; |
611 | ||
237fead6 MH |
612 | ecryptfs_printk(KERN_DEBUG, |
613 | "Initializing cipher [%s]; strlen = [%d]; " | |
f24b3887 | 614 | "key_size_bits = [%zd]\n", |
237fead6 MH |
615 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
616 | crypt_stat->key_size << 3); | |
cb69f36b | 617 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
618 | if (crypt_stat->tfm) { |
619 | rc = 0; | |
cb69f36b | 620 | goto out_unlock; |
237fead6 | 621 | } |
8bba066f MH |
622 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
623 | crypt_stat->cipher, "cbc"); | |
624 | if (rc) | |
c8161f64 | 625 | goto out_unlock; |
4dfea4f0 | 626 | crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0); |
de88777e AM |
627 | if (IS_ERR(crypt_stat->tfm)) { |
628 | rc = PTR_ERR(crypt_stat->tfm); | |
b0105eae | 629 | crypt_stat->tfm = NULL; |
237fead6 MH |
630 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
631 | "Error initializing cipher [%s]\n", | |
cb69f36b KC |
632 | full_alg_name); |
633 | goto out_free; | |
237fead6 | 634 | } |
4dfea4f0 | 635 | crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
237fead6 | 636 | rc = 0; |
cb69f36b KC |
637 | out_free: |
638 | kfree(full_alg_name); | |
c8161f64 ES |
639 | out_unlock: |
640 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
237fead6 MH |
641 | return rc; |
642 | } | |
643 | ||
644 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) | |
645 | { | |
646 | int extent_size_tmp; | |
647 | ||
648 | crypt_stat->extent_mask = 0xFFFFFFFF; | |
649 | crypt_stat->extent_shift = 0; | |
650 | if (crypt_stat->extent_size == 0) | |
651 | return; | |
652 | extent_size_tmp = crypt_stat->extent_size; | |
653 | while ((extent_size_tmp & 0x01) == 0) { | |
654 | extent_size_tmp >>= 1; | |
655 | crypt_stat->extent_mask <<= 1; | |
656 | crypt_stat->extent_shift++; | |
657 | } | |
658 | } | |
659 | ||
660 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) | |
661 | { | |
662 | /* Default values; may be overwritten as we are parsing the | |
663 | * packets. */ | |
664 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; | |
665 | set_extent_mask_and_shift(crypt_stat); | |
666 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; | |
dd2a3b7a | 667 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
fa3ef1cb | 668 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 MH |
669 | else { |
670 | if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) | |
fa3ef1cb | 671 | crypt_stat->metadata_size = |
cc11beff | 672 | ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 | 673 | else |
fa3ef1cb | 674 | crypt_stat->metadata_size = PAGE_CACHE_SIZE; |
45eaab79 | 675 | } |
237fead6 MH |
676 | } |
677 | ||
678 | /** | |
679 | * ecryptfs_compute_root_iv | |
680 | * @crypt_stats | |
681 | * | |
682 | * On error, sets the root IV to all 0's. | |
683 | */ | |
684 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) | |
685 | { | |
686 | int rc = 0; | |
687 | char dst[MD5_DIGEST_SIZE]; | |
688 | ||
689 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); | |
690 | BUG_ON(crypt_stat->iv_bytes <= 0); | |
e2bd99ec | 691 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
237fead6 MH |
692 | rc = -EINVAL; |
693 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " | |
694 | "cannot generate root IV\n"); | |
695 | goto out; | |
696 | } | |
697 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, | |
698 | crypt_stat->key_size); | |
699 | if (rc) { | |
700 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
701 | "MD5 while generating root IV\n"); | |
702 | goto out; | |
703 | } | |
704 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); | |
705 | out: | |
706 | if (rc) { | |
707 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); | |
e2bd99ec | 708 | crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING; |
237fead6 MH |
709 | } |
710 | return rc; | |
711 | } | |
712 | ||
713 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) | |
714 | { | |
715 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); | |
e2bd99ec | 716 | crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
237fead6 MH |
717 | ecryptfs_compute_root_iv(crypt_stat); |
718 | if (unlikely(ecryptfs_verbosity > 0)) { | |
719 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); | |
720 | ecryptfs_dump_hex(crypt_stat->key, | |
721 | crypt_stat->key_size); | |
722 | } | |
723 | } | |
724 | ||
17398957 MH |
725 | /** |
726 | * ecryptfs_copy_mount_wide_flags_to_inode_flags | |
22e78faf MH |
727 | * @crypt_stat: The inode's cryptographic context |
728 | * @mount_crypt_stat: The mount point's cryptographic context | |
17398957 MH |
729 | * |
730 | * This function propagates the mount-wide flags to individual inode | |
731 | * flags. | |
732 | */ | |
733 | static void ecryptfs_copy_mount_wide_flags_to_inode_flags( | |
734 | struct ecryptfs_crypt_stat *crypt_stat, | |
735 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
736 | { | |
737 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) | |
738 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
739 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
740 | crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; | |
addd65ad MH |
741 | if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { |
742 | crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES; | |
743 | if (mount_crypt_stat->flags | |
744 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK) | |
745 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK; | |
746 | else if (mount_crypt_stat->flags | |
747 | & ECRYPTFS_GLOBAL_ENCFN_USE_FEK) | |
748 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK; | |
749 | } | |
17398957 MH |
750 | } |
751 | ||
f4aad16a MH |
752 | static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs( |
753 | struct ecryptfs_crypt_stat *crypt_stat, | |
754 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
755 | { | |
756 | struct ecryptfs_global_auth_tok *global_auth_tok; | |
757 | int rc = 0; | |
758 | ||
aa06117f | 759 | mutex_lock(&crypt_stat->keysig_list_mutex); |
f4aad16a | 760 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
aa06117f | 761 | |
f4aad16a MH |
762 | list_for_each_entry(global_auth_tok, |
763 | &mount_crypt_stat->global_auth_tok_list, | |
764 | mount_crypt_stat_list) { | |
84814d64 TH |
765 | if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK) |
766 | continue; | |
f4aad16a MH |
767 | rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig); |
768 | if (rc) { | |
769 | printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc); | |
f4aad16a MH |
770 | goto out; |
771 | } | |
772 | } | |
aa06117f | 773 | |
f4aad16a | 774 | out: |
aa06117f RD |
775 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
776 | mutex_unlock(&crypt_stat->keysig_list_mutex); | |
f4aad16a MH |
777 | return rc; |
778 | } | |
779 | ||
237fead6 MH |
780 | /** |
781 | * ecryptfs_set_default_crypt_stat_vals | |
22e78faf MH |
782 | * @crypt_stat: The inode's cryptographic context |
783 | * @mount_crypt_stat: The mount point's cryptographic context | |
237fead6 MH |
784 | * |
785 | * Default values in the event that policy does not override them. | |
786 | */ | |
787 | static void ecryptfs_set_default_crypt_stat_vals( | |
788 | struct ecryptfs_crypt_stat *crypt_stat, | |
789 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
790 | { | |
17398957 MH |
791 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
792 | mount_crypt_stat); | |
237fead6 MH |
793 | ecryptfs_set_default_sizes(crypt_stat); |
794 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); | |
795 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; | |
e2bd99ec | 796 | crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID); |
237fead6 MH |
797 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
798 | crypt_stat->mount_crypt_stat = mount_crypt_stat; | |
799 | } | |
800 | ||
801 | /** | |
802 | * ecryptfs_new_file_context | |
b59db43a | 803 | * @ecryptfs_inode: The eCryptfs inode |
237fead6 MH |
804 | * |
805 | * If the crypto context for the file has not yet been established, | |
806 | * this is where we do that. Establishing a new crypto context | |
807 | * involves the following decisions: | |
808 | * - What cipher to use? | |
809 | * - What set of authentication tokens to use? | |
810 | * Here we just worry about getting enough information into the | |
811 | * authentication tokens so that we know that they are available. | |
812 | * We associate the available authentication tokens with the new file | |
813 | * via the set of signatures in the crypt_stat struct. Later, when | |
814 | * the headers are actually written out, we may again defer to | |
815 | * userspace to perform the encryption of the session key; for the | |
816 | * foreseeable future, this will be the case with public key packets. | |
817 | * | |
818 | * Returns zero on success; non-zero otherwise | |
819 | */ | |
b59db43a | 820 | int ecryptfs_new_file_context(struct inode *ecryptfs_inode) |
237fead6 | 821 | { |
237fead6 | 822 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 823 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
237fead6 MH |
824 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
825 | &ecryptfs_superblock_to_private( | |
b59db43a | 826 | ecryptfs_inode->i_sb)->mount_crypt_stat; |
237fead6 | 827 | int cipher_name_len; |
f4aad16a | 828 | int rc = 0; |
237fead6 MH |
829 | |
830 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); | |
af655dc6 | 831 | crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID); |
f4aad16a MH |
832 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
833 | mount_crypt_stat); | |
834 | rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat, | |
835 | mount_crypt_stat); | |
836 | if (rc) { | |
837 | printk(KERN_ERR "Error attempting to copy mount-wide key sigs " | |
838 | "to the inode key sigs; rc = [%d]\n", rc); | |
839 | goto out; | |
840 | } | |
841 | cipher_name_len = | |
842 | strlen(mount_crypt_stat->global_default_cipher_name); | |
843 | memcpy(crypt_stat->cipher, | |
844 | mount_crypt_stat->global_default_cipher_name, | |
845 | cipher_name_len); | |
846 | crypt_stat->cipher[cipher_name_len] = '\0'; | |
847 | crypt_stat->key_size = | |
848 | mount_crypt_stat->global_default_cipher_key_size; | |
849 | ecryptfs_generate_new_key(crypt_stat); | |
237fead6 MH |
850 | rc = ecryptfs_init_crypt_ctx(crypt_stat); |
851 | if (rc) | |
852 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " | |
853 | "context for cipher [%s]: rc = [%d]\n", | |
854 | crypt_stat->cipher, rc); | |
f4aad16a | 855 | out: |
237fead6 MH |
856 | return rc; |
857 | } | |
858 | ||
859 | /** | |
7a86617e | 860 | * ecryptfs_validate_marker - check for the ecryptfs marker |
237fead6 MH |
861 | * @data: The data block in which to check |
862 | * | |
7a86617e | 863 | * Returns zero if marker found; -EINVAL if not found |
237fead6 | 864 | */ |
7a86617e | 865 | static int ecryptfs_validate_marker(char *data) |
237fead6 MH |
866 | { |
867 | u32 m_1, m_2; | |
868 | ||
29335c6a HH |
869 | m_1 = get_unaligned_be32(data); |
870 | m_2 = get_unaligned_be32(data + 4); | |
237fead6 | 871 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
7a86617e | 872 | return 0; |
237fead6 MH |
873 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
874 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, | |
875 | MAGIC_ECRYPTFS_MARKER); | |
876 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " | |
877 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); | |
7a86617e | 878 | return -EINVAL; |
237fead6 MH |
879 | } |
880 | ||
881 | struct ecryptfs_flag_map_elem { | |
882 | u32 file_flag; | |
883 | u32 local_flag; | |
884 | }; | |
885 | ||
886 | /* Add support for additional flags by adding elements here. */ | |
887 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { | |
888 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, | |
dd2a3b7a | 889 | {0x00000002, ECRYPTFS_ENCRYPTED}, |
addd65ad MH |
890 | {0x00000004, ECRYPTFS_METADATA_IN_XATTR}, |
891 | {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES} | |
237fead6 MH |
892 | }; |
893 | ||
894 | /** | |
895 | * ecryptfs_process_flags | |
22e78faf | 896 | * @crypt_stat: The cryptographic context |
237fead6 MH |
897 | * @page_virt: Source data to be parsed |
898 | * @bytes_read: Updated with the number of bytes read | |
899 | * | |
900 | * Returns zero on success; non-zero if the flag set is invalid | |
901 | */ | |
902 | static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, | |
903 | char *page_virt, int *bytes_read) | |
904 | { | |
905 | int rc = 0; | |
906 | int i; | |
907 | u32 flags; | |
908 | ||
29335c6a | 909 | flags = get_unaligned_be32(page_virt); |
237fead6 MH |
910 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) |
911 | / sizeof(struct ecryptfs_flag_map_elem))); i++) | |
912 | if (flags & ecryptfs_flag_map[i].file_flag) { | |
e2bd99ec | 913 | crypt_stat->flags |= ecryptfs_flag_map[i].local_flag; |
237fead6 | 914 | } else |
e2bd99ec | 915 | crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag); |
237fead6 MH |
916 | /* Version is in top 8 bits of the 32-bit flag vector */ |
917 | crypt_stat->file_version = ((flags >> 24) & 0xFF); | |
918 | (*bytes_read) = 4; | |
919 | return rc; | |
920 | } | |
921 | ||
922 | /** | |
923 | * write_ecryptfs_marker | |
924 | * @page_virt: The pointer to in a page to begin writing the marker | |
925 | * @written: Number of bytes written | |
926 | * | |
927 | * Marker = 0x3c81b7f5 | |
928 | */ | |
929 | static void write_ecryptfs_marker(char *page_virt, size_t *written) | |
930 | { | |
931 | u32 m_1, m_2; | |
932 | ||
933 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
934 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); | |
29335c6a HH |
935 | put_unaligned_be32(m_1, page_virt); |
936 | page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2); | |
937 | put_unaligned_be32(m_2, page_virt); | |
237fead6 MH |
938 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
939 | } | |
940 | ||
f4e60e6b TH |
941 | void ecryptfs_write_crypt_stat_flags(char *page_virt, |
942 | struct ecryptfs_crypt_stat *crypt_stat, | |
943 | size_t *written) | |
237fead6 MH |
944 | { |
945 | u32 flags = 0; | |
946 | int i; | |
947 | ||
948 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) | |
949 | / sizeof(struct ecryptfs_flag_map_elem))); i++) | |
e2bd99ec | 950 | if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag) |
237fead6 MH |
951 | flags |= ecryptfs_flag_map[i].file_flag; |
952 | /* Version is in top 8 bits of the 32-bit flag vector */ | |
953 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); | |
29335c6a | 954 | put_unaligned_be32(flags, page_virt); |
237fead6 MH |
955 | (*written) = 4; |
956 | } | |
957 | ||
958 | struct ecryptfs_cipher_code_str_map_elem { | |
959 | char cipher_str[16]; | |
19e66a67 | 960 | u8 cipher_code; |
237fead6 MH |
961 | }; |
962 | ||
963 | /* Add support for additional ciphers by adding elements here. The | |
964 | * cipher_code is whatever OpenPGP applicatoins use to identify the | |
965 | * ciphers. List in order of probability. */ | |
966 | static struct ecryptfs_cipher_code_str_map_elem | |
967 | ecryptfs_cipher_code_str_map[] = { | |
968 | {"aes",RFC2440_CIPHER_AES_128 }, | |
969 | {"blowfish", RFC2440_CIPHER_BLOWFISH}, | |
970 | {"des3_ede", RFC2440_CIPHER_DES3_EDE}, | |
971 | {"cast5", RFC2440_CIPHER_CAST_5}, | |
972 | {"twofish", RFC2440_CIPHER_TWOFISH}, | |
973 | {"cast6", RFC2440_CIPHER_CAST_6}, | |
974 | {"aes", RFC2440_CIPHER_AES_192}, | |
975 | {"aes", RFC2440_CIPHER_AES_256} | |
976 | }; | |
977 | ||
978 | /** | |
979 | * ecryptfs_code_for_cipher_string | |
9c79f34f MH |
980 | * @cipher_name: The string alias for the cipher |
981 | * @key_bytes: Length of key in bytes; used for AES code selection | |
237fead6 MH |
982 | * |
983 | * Returns zero on no match, or the cipher code on match | |
984 | */ | |
9c79f34f | 985 | u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes) |
237fead6 MH |
986 | { |
987 | int i; | |
19e66a67 | 988 | u8 code = 0; |
237fead6 MH |
989 | struct ecryptfs_cipher_code_str_map_elem *map = |
990 | ecryptfs_cipher_code_str_map; | |
991 | ||
9c79f34f MH |
992 | if (strcmp(cipher_name, "aes") == 0) { |
993 | switch (key_bytes) { | |
237fead6 MH |
994 | case 16: |
995 | code = RFC2440_CIPHER_AES_128; | |
996 | break; | |
997 | case 24: | |
998 | code = RFC2440_CIPHER_AES_192; | |
999 | break; | |
1000 | case 32: | |
1001 | code = RFC2440_CIPHER_AES_256; | |
1002 | } | |
1003 | } else { | |
1004 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
9c79f34f | 1005 | if (strcmp(cipher_name, map[i].cipher_str) == 0) { |
237fead6 MH |
1006 | code = map[i].cipher_code; |
1007 | break; | |
1008 | } | |
1009 | } | |
1010 | return code; | |
1011 | } | |
1012 | ||
1013 | /** | |
1014 | * ecryptfs_cipher_code_to_string | |
1015 | * @str: Destination to write out the cipher name | |
1016 | * @cipher_code: The code to convert to cipher name string | |
1017 | * | |
1018 | * Returns zero on success | |
1019 | */ | |
19e66a67 | 1020 | int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code) |
237fead6 MH |
1021 | { |
1022 | int rc = 0; | |
1023 | int i; | |
1024 | ||
1025 | str[0] = '\0'; | |
1026 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
1027 | if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) | |
1028 | strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); | |
1029 | if (str[0] == '\0') { | |
1030 | ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " | |
1031 | "[%d]\n", cipher_code); | |
1032 | rc = -EINVAL; | |
1033 | } | |
1034 | return rc; | |
1035 | } | |
1036 | ||
778aeb42 | 1037 | int ecryptfs_read_and_validate_header_region(struct inode *inode) |
dd2a3b7a | 1038 | { |
778aeb42 TH |
1039 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
1040 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
1041 | int rc; |
1042 | ||
778aeb42 TH |
1043 | rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES, |
1044 | inode); | |
1045 | if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
1046 | return rc >= 0 ? -EINVAL : rc; | |
1047 | rc = ecryptfs_validate_marker(marker); | |
1048 | if (!rc) | |
1049 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
1050 | return rc; |
1051 | } | |
1052 | ||
e77a56dd MH |
1053 | void |
1054 | ecryptfs_write_header_metadata(char *virt, | |
1055 | struct ecryptfs_crypt_stat *crypt_stat, | |
1056 | size_t *written) | |
237fead6 MH |
1057 | { |
1058 | u32 header_extent_size; | |
1059 | u16 num_header_extents_at_front; | |
1060 | ||
45eaab79 | 1061 | header_extent_size = (u32)crypt_stat->extent_size; |
237fead6 | 1062 | num_header_extents_at_front = |
fa3ef1cb | 1063 | (u16)(crypt_stat->metadata_size / crypt_stat->extent_size); |
29335c6a | 1064 | put_unaligned_be32(header_extent_size, virt); |
237fead6 | 1065 | virt += 4; |
29335c6a | 1066 | put_unaligned_be16(num_header_extents_at_front, virt); |
237fead6 MH |
1067 | (*written) = 6; |
1068 | } | |
1069 | ||
30632870 | 1070 | struct kmem_cache *ecryptfs_header_cache; |
237fead6 MH |
1071 | |
1072 | /** | |
1073 | * ecryptfs_write_headers_virt | |
22e78faf | 1074 | * @page_virt: The virtual address to write the headers to |
87b811c3 | 1075 | * @max: The size of memory allocated at page_virt |
22e78faf MH |
1076 | * @size: Set to the number of bytes written by this function |
1077 | * @crypt_stat: The cryptographic context | |
1078 | * @ecryptfs_dentry: The eCryptfs dentry | |
237fead6 MH |
1079 | * |
1080 | * Format version: 1 | |
1081 | * | |
1082 | * Header Extent: | |
1083 | * Octets 0-7: Unencrypted file size (big-endian) | |
1084 | * Octets 8-15: eCryptfs special marker | |
1085 | * Octets 16-19: Flags | |
1086 | * Octet 16: File format version number (between 0 and 255) | |
1087 | * Octets 17-18: Reserved | |
1088 | * Octet 19: Bit 1 (lsb): Reserved | |
1089 | * Bit 2: Encrypted? | |
1090 | * Bits 3-8: Reserved | |
1091 | * Octets 20-23: Header extent size (big-endian) | |
1092 | * Octets 24-25: Number of header extents at front of file | |
1093 | * (big-endian) | |
1094 | * Octet 26: Begin RFC 2440 authentication token packet set | |
1095 | * Data Extent 0: | |
1096 | * Lower data (CBC encrypted) | |
1097 | * Data Extent 1: | |
1098 | * Lower data (CBC encrypted) | |
1099 | * ... | |
1100 | * | |
1101 | * Returns zero on success | |
1102 | */ | |
87b811c3 ES |
1103 | static int ecryptfs_write_headers_virt(char *page_virt, size_t max, |
1104 | size_t *size, | |
dd2a3b7a MH |
1105 | struct ecryptfs_crypt_stat *crypt_stat, |
1106 | struct dentry *ecryptfs_dentry) | |
237fead6 MH |
1107 | { |
1108 | int rc; | |
1109 | size_t written; | |
1110 | size_t offset; | |
1111 | ||
1112 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1113 | write_ecryptfs_marker((page_virt + offset), &written); | |
1114 | offset += written; | |
f4e60e6b TH |
1115 | ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat, |
1116 | &written); | |
237fead6 | 1117 | offset += written; |
e77a56dd MH |
1118 | ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
1119 | &written); | |
237fead6 MH |
1120 | offset += written; |
1121 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, | |
1122 | ecryptfs_dentry, &written, | |
87b811c3 | 1123 | max - offset); |
237fead6 MH |
1124 | if (rc) |
1125 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " | |
1126 | "set; rc = [%d]\n", rc); | |
dd2a3b7a MH |
1127 | if (size) { |
1128 | offset += written; | |
1129 | *size = offset; | |
1130 | } | |
1131 | return rc; | |
1132 | } | |
1133 | ||
22e78faf | 1134 | static int |
b59db43a | 1135 | ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode, |
8faece5f | 1136 | char *virt, size_t virt_len) |
dd2a3b7a | 1137 | { |
d7cdc5fe | 1138 | int rc; |
dd2a3b7a | 1139 | |
b59db43a | 1140 | rc = ecryptfs_write_lower(ecryptfs_inode, virt, |
8faece5f | 1141 | 0, virt_len); |
96a7b9c2 | 1142 | if (rc < 0) |
d7cdc5fe | 1143 | printk(KERN_ERR "%s: Error attempting to write header " |
96a7b9c2 TH |
1144 | "information to lower file; rc = [%d]\n", __func__, rc); |
1145 | else | |
1146 | rc = 0; | |
70456600 | 1147 | return rc; |
dd2a3b7a MH |
1148 | } |
1149 | ||
22e78faf MH |
1150 | static int |
1151 | ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, | |
22e78faf | 1152 | char *page_virt, size_t size) |
dd2a3b7a MH |
1153 | { |
1154 | int rc; | |
1155 | ||
1156 | rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt, | |
1157 | size, 0); | |
237fead6 MH |
1158 | return rc; |
1159 | } | |
1160 | ||
8faece5f TH |
1161 | static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask, |
1162 | unsigned int order) | |
1163 | { | |
1164 | struct page *page; | |
1165 | ||
1166 | page = alloc_pages(gfp_mask | __GFP_ZERO, order); | |
1167 | if (page) | |
1168 | return (unsigned long) page_address(page); | |
1169 | return 0; | |
1170 | } | |
1171 | ||
237fead6 | 1172 | /** |
dd2a3b7a | 1173 | * ecryptfs_write_metadata |
b59db43a TH |
1174 | * @ecryptfs_dentry: The eCryptfs dentry, which should be negative |
1175 | * @ecryptfs_inode: The newly created eCryptfs inode | |
237fead6 MH |
1176 | * |
1177 | * Write the file headers out. This will likely involve a userspace | |
1178 | * callout, in which the session key is encrypted with one or more | |
1179 | * public keys and/or the passphrase necessary to do the encryption is | |
1180 | * retrieved via a prompt. Exactly what happens at this point should | |
1181 | * be policy-dependent. | |
1182 | * | |
1183 | * Returns zero on success; non-zero on error | |
1184 | */ | |
b59db43a TH |
1185 | int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry, |
1186 | struct inode *ecryptfs_inode) | |
237fead6 | 1187 | { |
d7cdc5fe | 1188 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 1189 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
8faece5f | 1190 | unsigned int order; |
cc11beff | 1191 | char *virt; |
8faece5f | 1192 | size_t virt_len; |
d7cdc5fe | 1193 | size_t size = 0; |
237fead6 MH |
1194 | int rc = 0; |
1195 | ||
e2bd99ec MH |
1196 | if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
1197 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { | |
d7cdc5fe | 1198 | printk(KERN_ERR "Key is invalid; bailing out\n"); |
237fead6 MH |
1199 | rc = -EINVAL; |
1200 | goto out; | |
1201 | } | |
1202 | } else { | |
cc11beff | 1203 | printk(KERN_WARNING "%s: Encrypted flag not set\n", |
18d1dbf1 | 1204 | __func__); |
237fead6 | 1205 | rc = -EINVAL; |
237fead6 MH |
1206 | goto out; |
1207 | } | |
fa3ef1cb | 1208 | virt_len = crypt_stat->metadata_size; |
8faece5f | 1209 | order = get_order(virt_len); |
237fead6 | 1210 | /* Released in this function */ |
8faece5f | 1211 | virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order); |
cc11beff | 1212 | if (!virt) { |
18d1dbf1 | 1213 | printk(KERN_ERR "%s: Out of memory\n", __func__); |
237fead6 MH |
1214 | rc = -ENOMEM; |
1215 | goto out; | |
1216 | } | |
bd4f0fe8 | 1217 | /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */ |
8faece5f TH |
1218 | rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat, |
1219 | ecryptfs_dentry); | |
237fead6 | 1220 | if (unlikely(rc)) { |
cc11beff | 1221 | printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n", |
18d1dbf1 | 1222 | __func__, rc); |
237fead6 MH |
1223 | goto out_free; |
1224 | } | |
dd2a3b7a | 1225 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
8faece5f TH |
1226 | rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt, |
1227 | size); | |
dd2a3b7a | 1228 | else |
b59db43a | 1229 | rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt, |
8faece5f | 1230 | virt_len); |
dd2a3b7a | 1231 | if (rc) { |
cc11beff | 1232 | printk(KERN_ERR "%s: Error writing metadata out to lower file; " |
18d1dbf1 | 1233 | "rc = [%d]\n", __func__, rc); |
dd2a3b7a | 1234 | goto out_free; |
237fead6 | 1235 | } |
237fead6 | 1236 | out_free: |
8faece5f | 1237 | free_pages((unsigned long)virt, order); |
237fead6 MH |
1238 | out: |
1239 | return rc; | |
1240 | } | |
1241 | ||
dd2a3b7a MH |
1242 | #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
1243 | #define ECRYPTFS_VALIDATE_HEADER_SIZE 1 | |
237fead6 | 1244 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
dd2a3b7a MH |
1245 | char *virt, int *bytes_read, |
1246 | int validate_header_size) | |
237fead6 MH |
1247 | { |
1248 | int rc = 0; | |
1249 | u32 header_extent_size; | |
1250 | u16 num_header_extents_at_front; | |
1251 | ||
29335c6a HH |
1252 | header_extent_size = get_unaligned_be32(virt); |
1253 | virt += sizeof(__be32); | |
1254 | num_header_extents_at_front = get_unaligned_be16(virt); | |
fa3ef1cb TH |
1255 | crypt_stat->metadata_size = (((size_t)num_header_extents_at_front |
1256 | * (size_t)header_extent_size)); | |
29335c6a | 1257 | (*bytes_read) = (sizeof(__be32) + sizeof(__be16)); |
dd2a3b7a | 1258 | if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
fa3ef1cb | 1259 | && (crypt_stat->metadata_size |
dd2a3b7a | 1260 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { |
237fead6 | 1261 | rc = -EINVAL; |
cc11beff | 1262 | printk(KERN_WARNING "Invalid header size: [%zd]\n", |
fa3ef1cb | 1263 | crypt_stat->metadata_size); |
237fead6 MH |
1264 | } |
1265 | return rc; | |
1266 | } | |
1267 | ||
1268 | /** | |
1269 | * set_default_header_data | |
22e78faf | 1270 | * @crypt_stat: The cryptographic context |
237fead6 MH |
1271 | * |
1272 | * For version 0 file format; this function is only for backwards | |
1273 | * compatibility for files created with the prior versions of | |
1274 | * eCryptfs. | |
1275 | */ | |
1276 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) | |
1277 | { | |
fa3ef1cb | 1278 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
237fead6 MH |
1279 | } |
1280 | ||
3aeb86ea TH |
1281 | void ecryptfs_i_size_init(const char *page_virt, struct inode *inode) |
1282 | { | |
1283 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; | |
1284 | struct ecryptfs_crypt_stat *crypt_stat; | |
1285 | u64 file_size; | |
1286 | ||
1287 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
1288 | mount_crypt_stat = | |
1289 | &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat; | |
1290 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { | |
1291 | file_size = i_size_read(ecryptfs_inode_to_lower(inode)); | |
1292 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) | |
1293 | file_size += crypt_stat->metadata_size; | |
1294 | } else | |
1295 | file_size = get_unaligned_be64(page_virt); | |
1296 | i_size_write(inode, (loff_t)file_size); | |
1297 | crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED; | |
1298 | } | |
1299 | ||
237fead6 MH |
1300 | /** |
1301 | * ecryptfs_read_headers_virt | |
22e78faf MH |
1302 | * @page_virt: The virtual address into which to read the headers |
1303 | * @crypt_stat: The cryptographic context | |
1304 | * @ecryptfs_dentry: The eCryptfs dentry | |
1305 | * @validate_header_size: Whether to validate the header size while reading | |
237fead6 MH |
1306 | * |
1307 | * Read/parse the header data. The header format is detailed in the | |
1308 | * comment block for the ecryptfs_write_headers_virt() function. | |
1309 | * | |
1310 | * Returns zero on success | |
1311 | */ | |
1312 | static int ecryptfs_read_headers_virt(char *page_virt, | |
1313 | struct ecryptfs_crypt_stat *crypt_stat, | |
dd2a3b7a MH |
1314 | struct dentry *ecryptfs_dentry, |
1315 | int validate_header_size) | |
237fead6 MH |
1316 | { |
1317 | int rc = 0; | |
1318 | int offset; | |
1319 | int bytes_read; | |
1320 | ||
1321 | ecryptfs_set_default_sizes(crypt_stat); | |
1322 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( | |
1323 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
1324 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
7a86617e TH |
1325 | rc = ecryptfs_validate_marker(page_virt + offset); |
1326 | if (rc) | |
237fead6 | 1327 | goto out; |
3aeb86ea TH |
1328 | if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED)) |
1329 | ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode); | |
237fead6 MH |
1330 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
1331 | rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset), | |
1332 | &bytes_read); | |
1333 | if (rc) { | |
1334 | ecryptfs_printk(KERN_WARNING, "Error processing flags\n"); | |
1335 | goto out; | |
1336 | } | |
1337 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { | |
1338 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " | |
1339 | "file version [%d] is supported by this " | |
1340 | "version of eCryptfs\n", | |
1341 | crypt_stat->file_version, | |
1342 | ECRYPTFS_SUPPORTED_FILE_VERSION); | |
1343 | rc = -EINVAL; | |
1344 | goto out; | |
1345 | } | |
1346 | offset += bytes_read; | |
1347 | if (crypt_stat->file_version >= 1) { | |
1348 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), | |
dd2a3b7a | 1349 | &bytes_read, validate_header_size); |
237fead6 MH |
1350 | if (rc) { |
1351 | ecryptfs_printk(KERN_WARNING, "Error reading header " | |
1352 | "metadata; rc = [%d]\n", rc); | |
1353 | } | |
1354 | offset += bytes_read; | |
1355 | } else | |
1356 | set_default_header_data(crypt_stat); | |
1357 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), | |
1358 | ecryptfs_dentry); | |
1359 | out: | |
1360 | return rc; | |
1361 | } | |
1362 | ||
1363 | /** | |
dd2a3b7a | 1364 | * ecryptfs_read_xattr_region |
22e78faf | 1365 | * @page_virt: The vitual address into which to read the xattr data |
2ed92554 | 1366 | * @ecryptfs_inode: The eCryptfs inode |
dd2a3b7a MH |
1367 | * |
1368 | * Attempts to read the crypto metadata from the extended attribute | |
1369 | * region of the lower file. | |
22e78faf MH |
1370 | * |
1371 | * Returns zero on success; non-zero on error | |
dd2a3b7a | 1372 | */ |
d7cdc5fe | 1373 | int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) |
dd2a3b7a | 1374 | { |
d7cdc5fe MH |
1375 | struct dentry *lower_dentry = |
1376 | ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry; | |
dd2a3b7a MH |
1377 | ssize_t size; |
1378 | int rc = 0; | |
1379 | ||
d7cdc5fe MH |
1380 | size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME, |
1381 | page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); | |
dd2a3b7a | 1382 | if (size < 0) { |
25bd8174 MH |
1383 | if (unlikely(ecryptfs_verbosity > 0)) |
1384 | printk(KERN_INFO "Error attempting to read the [%s] " | |
1385 | "xattr from the lower file; return value = " | |
1386 | "[%zd]\n", ECRYPTFS_XATTR_NAME, size); | |
dd2a3b7a MH |
1387 | rc = -EINVAL; |
1388 | goto out; | |
1389 | } | |
1390 | out: | |
1391 | return rc; | |
1392 | } | |
1393 | ||
778aeb42 | 1394 | int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, |
3b06b3eb | 1395 | struct inode *inode) |
dd2a3b7a | 1396 | { |
778aeb42 TH |
1397 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
1398 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
1399 | int rc; |
1400 | ||
778aeb42 TH |
1401 | rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), |
1402 | ECRYPTFS_XATTR_NAME, file_size, | |
1403 | ECRYPTFS_SIZE_AND_MARKER_BYTES); | |
1404 | if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
1405 | return rc >= 0 ? -EINVAL : rc; | |
1406 | rc = ecryptfs_validate_marker(marker); | |
1407 | if (!rc) | |
1408 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
1409 | return rc; |
1410 | } | |
1411 | ||
1412 | /** | |
1413 | * ecryptfs_read_metadata | |
1414 | * | |
1415 | * Common entry point for reading file metadata. From here, we could | |
1416 | * retrieve the header information from the header region of the file, | |
1417 | * the xattr region of the file, or some other repostory that is | |
1418 | * stored separately from the file itself. The current implementation | |
1419 | * supports retrieving the metadata information from the file contents | |
1420 | * and from the xattr region. | |
237fead6 MH |
1421 | * |
1422 | * Returns zero if valid headers found and parsed; non-zero otherwise | |
1423 | */ | |
d7cdc5fe | 1424 | int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) |
237fead6 | 1425 | { |
bb450361 TG |
1426 | int rc; |
1427 | char *page_virt; | |
d7cdc5fe | 1428 | struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; |
237fead6 | 1429 | struct ecryptfs_crypt_stat *crypt_stat = |
d7cdc5fe | 1430 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
e77a56dd MH |
1431 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
1432 | &ecryptfs_superblock_to_private( | |
1433 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
237fead6 | 1434 | |
e77a56dd MH |
1435 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
1436 | mount_crypt_stat); | |
237fead6 | 1437 | /* Read the first page from the underlying file */ |
30632870 | 1438 | page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER); |
237fead6 MH |
1439 | if (!page_virt) { |
1440 | rc = -ENOMEM; | |
d7cdc5fe | 1441 | printk(KERN_ERR "%s: Unable to allocate page_virt\n", |
18d1dbf1 | 1442 | __func__); |
237fead6 MH |
1443 | goto out; |
1444 | } | |
d7cdc5fe MH |
1445 | rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size, |
1446 | ecryptfs_inode); | |
96a7b9c2 | 1447 | if (rc >= 0) |
d7cdc5fe MH |
1448 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
1449 | ecryptfs_dentry, | |
1450 | ECRYPTFS_VALIDATE_HEADER_SIZE); | |
237fead6 | 1451 | if (rc) { |
bb450361 | 1452 | /* metadata is not in the file header, so try xattrs */ |
1984c23f | 1453 | memset(page_virt, 0, PAGE_CACHE_SIZE); |
d7cdc5fe | 1454 | rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); |
dd2a3b7a MH |
1455 | if (rc) { |
1456 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1457 | "file header region or xattr region, inode %lu\n", |
1458 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1459 | rc = -EINVAL; |
1460 | goto out; | |
1461 | } | |
1462 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, | |
1463 | ecryptfs_dentry, | |
1464 | ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); | |
1465 | if (rc) { | |
1466 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1467 | "file xattr region either, inode %lu\n", |
1468 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1469 | rc = -EINVAL; |
1470 | } | |
1471 | if (crypt_stat->mount_crypt_stat->flags | |
1472 | & ECRYPTFS_XATTR_METADATA_ENABLED) { | |
1473 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
1474 | } else { | |
1475 | printk(KERN_WARNING "Attempt to access file with " | |
1476 | "crypto metadata only in the extended attribute " | |
1477 | "region, but eCryptfs was mounted without " | |
1478 | "xattr support enabled. eCryptfs will not treat " | |
30373dc0 TG |
1479 | "this like an encrypted file, inode %lu\n", |
1480 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1481 | rc = -EINVAL; |
1482 | } | |
237fead6 MH |
1483 | } |
1484 | out: | |
1485 | if (page_virt) { | |
1486 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
30632870 | 1487 | kmem_cache_free(ecryptfs_header_cache, page_virt); |
237fead6 MH |
1488 | } |
1489 | return rc; | |
1490 | } | |
1491 | ||
51ca58dc MH |
1492 | /** |
1493 | * ecryptfs_encrypt_filename - encrypt filename | |
1494 | * | |
1495 | * CBC-encrypts the filename. We do not want to encrypt the same | |
1496 | * filename with the same key and IV, which may happen with hard | |
1497 | * links, so we prepend random bits to each filename. | |
1498 | * | |
1499 | * Returns zero on success; non-zero otherwise | |
1500 | */ | |
1501 | static int | |
1502 | ecryptfs_encrypt_filename(struct ecryptfs_filename *filename, | |
1503 | struct ecryptfs_crypt_stat *crypt_stat, | |
1504 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
1505 | { | |
1506 | int rc = 0; | |
1507 | ||
1508 | filename->encrypted_filename = NULL; | |
1509 | filename->encrypted_filename_size = 0; | |
1510 | if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK)) | |
1511 | || (mount_crypt_stat && (mount_crypt_stat->flags | |
1512 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) { | |
1513 | size_t packet_size; | |
1514 | size_t remaining_bytes; | |
1515 | ||
1516 | rc = ecryptfs_write_tag_70_packet( | |
1517 | NULL, NULL, | |
1518 | &filename->encrypted_filename_size, | |
1519 | mount_crypt_stat, NULL, | |
1520 | filename->filename_size); | |
1521 | if (rc) { | |
1522 | printk(KERN_ERR "%s: Error attempting to get packet " | |
1523 | "size for tag 72; rc = [%d]\n", __func__, | |
1524 | rc); | |
1525 | filename->encrypted_filename_size = 0; | |
1526 | goto out; | |
1527 | } | |
1528 | filename->encrypted_filename = | |
1529 | kmalloc(filename->encrypted_filename_size, GFP_KERNEL); | |
1530 | if (!filename->encrypted_filename) { | |
1531 | printk(KERN_ERR "%s: Out of memory whilst attempting " | |
df261c52 | 1532 | "to kmalloc [%zd] bytes\n", __func__, |
51ca58dc MH |
1533 | filename->encrypted_filename_size); |
1534 | rc = -ENOMEM; | |
1535 | goto out; | |
1536 | } | |
1537 | remaining_bytes = filename->encrypted_filename_size; | |
1538 | rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename, | |
1539 | &remaining_bytes, | |
1540 | &packet_size, | |
1541 | mount_crypt_stat, | |
1542 | filename->filename, | |
1543 | filename->filename_size); | |
1544 | if (rc) { | |
1545 | printk(KERN_ERR "%s: Error attempting to generate " | |
1546 | "tag 70 packet; rc = [%d]\n", __func__, | |
1547 | rc); | |
1548 | kfree(filename->encrypted_filename); | |
1549 | filename->encrypted_filename = NULL; | |
1550 | filename->encrypted_filename_size = 0; | |
1551 | goto out; | |
1552 | } | |
1553 | filename->encrypted_filename_size = packet_size; | |
1554 | } else { | |
1555 | printk(KERN_ERR "%s: No support for requested filename " | |
1556 | "encryption method in this release\n", __func__); | |
df6ad33b | 1557 | rc = -EOPNOTSUPP; |
51ca58dc MH |
1558 | goto out; |
1559 | } | |
1560 | out: | |
1561 | return rc; | |
1562 | } | |
1563 | ||
1564 | static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size, | |
1565 | const char *name, size_t name_size) | |
1566 | { | |
1567 | int rc = 0; | |
1568 | ||
fd9fc842 | 1569 | (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL); |
51ca58dc MH |
1570 | if (!(*copied_name)) { |
1571 | rc = -ENOMEM; | |
1572 | goto out; | |
1573 | } | |
1574 | memcpy((void *)(*copied_name), (void *)name, name_size); | |
1575 | (*copied_name)[(name_size)] = '\0'; /* Only for convenience | |
1576 | * in printing out the | |
1577 | * string in debug | |
1578 | * messages */ | |
fd9fc842 | 1579 | (*copied_name_size) = name_size; |
51ca58dc MH |
1580 | out: |
1581 | return rc; | |
1582 | } | |
1583 | ||
237fead6 | 1584 | /** |
f4aad16a | 1585 | * ecryptfs_process_key_cipher - Perform key cipher initialization. |
237fead6 | 1586 | * @key_tfm: Crypto context for key material, set by this function |
e5d9cbde MH |
1587 | * @cipher_name: Name of the cipher |
1588 | * @key_size: Size of the key in bytes | |
237fead6 MH |
1589 | * |
1590 | * Returns zero on success. Any crypto_tfm structs allocated here | |
1591 | * should be released by other functions, such as on a superblock put | |
1592 | * event, regardless of whether this function succeeds for fails. | |
1593 | */ | |
cd9d67df | 1594 | static int |
f4aad16a MH |
1595 | ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm, |
1596 | char *cipher_name, size_t *key_size) | |
237fead6 MH |
1597 | { |
1598 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; | |
ece550f5 | 1599 | char *full_alg_name = NULL; |
237fead6 MH |
1600 | int rc; |
1601 | ||
e5d9cbde MH |
1602 | *key_tfm = NULL; |
1603 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { | |
237fead6 | 1604 | rc = -EINVAL; |
df261c52 | 1605 | printk(KERN_ERR "Requested key size is [%zd] bytes; maximum " |
e5d9cbde | 1606 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
237fead6 MH |
1607 | goto out; |
1608 | } | |
8bba066f MH |
1609 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
1610 | "ecb"); | |
1611 | if (rc) | |
1612 | goto out; | |
1613 | *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); | |
8bba066f MH |
1614 | if (IS_ERR(*key_tfm)) { |
1615 | rc = PTR_ERR(*key_tfm); | |
237fead6 | 1616 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
38268498 | 1617 | "[%s]; rc = [%d]\n", full_alg_name, rc); |
237fead6 MH |
1618 | goto out; |
1619 | } | |
8bba066f MH |
1620 | crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
1621 | if (*key_size == 0) { | |
1622 | struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm); | |
1623 | ||
1624 | *key_size = alg->max_keysize; | |
1625 | } | |
e5d9cbde | 1626 | get_random_bytes(dummy_key, *key_size); |
8bba066f | 1627 | rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size); |
237fead6 | 1628 | if (rc) { |
df261c52 | 1629 | printk(KERN_ERR "Error attempting to set key of size [%zd] for " |
38268498 DH |
1630 | "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name, |
1631 | rc); | |
237fead6 MH |
1632 | rc = -EINVAL; |
1633 | goto out; | |
1634 | } | |
1635 | out: | |
ece550f5 | 1636 | kfree(full_alg_name); |
237fead6 MH |
1637 | return rc; |
1638 | } | |
f4aad16a MH |
1639 | |
1640 | struct kmem_cache *ecryptfs_key_tfm_cache; | |
7896b631 | 1641 | static struct list_head key_tfm_list; |
af440f52 | 1642 | struct mutex key_tfm_list_mutex; |
f4aad16a | 1643 | |
7371a382 | 1644 | int __init ecryptfs_init_crypto(void) |
f4aad16a MH |
1645 | { |
1646 | mutex_init(&key_tfm_list_mutex); | |
1647 | INIT_LIST_HEAD(&key_tfm_list); | |
1648 | return 0; | |
1649 | } | |
1650 | ||
af440f52 ES |
1651 | /** |
1652 | * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list | |
1653 | * | |
1654 | * Called only at module unload time | |
1655 | */ | |
fcd12835 | 1656 | int ecryptfs_destroy_crypto(void) |
f4aad16a MH |
1657 | { |
1658 | struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp; | |
1659 | ||
1660 | mutex_lock(&key_tfm_list_mutex); | |
1661 | list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list, | |
1662 | key_tfm_list) { | |
1663 | list_del(&key_tfm->key_tfm_list); | |
1664 | if (key_tfm->key_tfm) | |
1665 | crypto_free_blkcipher(key_tfm->key_tfm); | |
1666 | kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm); | |
1667 | } | |
1668 | mutex_unlock(&key_tfm_list_mutex); | |
1669 | return 0; | |
1670 | } | |
1671 | ||
1672 | int | |
1673 | ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, | |
1674 | size_t key_size) | |
1675 | { | |
1676 | struct ecryptfs_key_tfm *tmp_tfm; | |
1677 | int rc = 0; | |
1678 | ||
af440f52 ES |
1679 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
1680 | ||
f4aad16a MH |
1681 | tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL); |
1682 | if (key_tfm != NULL) | |
1683 | (*key_tfm) = tmp_tfm; | |
1684 | if (!tmp_tfm) { | |
1685 | rc = -ENOMEM; | |
1686 | printk(KERN_ERR "Error attempting to allocate from " | |
1687 | "ecryptfs_key_tfm_cache\n"); | |
1688 | goto out; | |
1689 | } | |
1690 | mutex_init(&tmp_tfm->key_tfm_mutex); | |
1691 | strncpy(tmp_tfm->cipher_name, cipher_name, | |
1692 | ECRYPTFS_MAX_CIPHER_NAME_SIZE); | |
b8862906 | 1693 | tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; |
f4aad16a | 1694 | tmp_tfm->key_size = key_size; |
5dda6992 MH |
1695 | rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, |
1696 | tmp_tfm->cipher_name, | |
1697 | &tmp_tfm->key_size); | |
1698 | if (rc) { | |
f4aad16a MH |
1699 | printk(KERN_ERR "Error attempting to initialize key TFM " |
1700 | "cipher with name = [%s]; rc = [%d]\n", | |
1701 | tmp_tfm->cipher_name, rc); | |
1702 | kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm); | |
1703 | if (key_tfm != NULL) | |
1704 | (*key_tfm) = NULL; | |
1705 | goto out; | |
1706 | } | |
f4aad16a | 1707 | list_add(&tmp_tfm->key_tfm_list, &key_tfm_list); |
f4aad16a MH |
1708 | out: |
1709 | return rc; | |
1710 | } | |
1711 | ||
af440f52 ES |
1712 | /** |
1713 | * ecryptfs_tfm_exists - Search for existing tfm for cipher_name. | |
1714 | * @cipher_name: the name of the cipher to search for | |
1715 | * @key_tfm: set to corresponding tfm if found | |
1716 | * | |
1717 | * Searches for cached key_tfm matching @cipher_name | |
1718 | * Must be called with &key_tfm_list_mutex held | |
1719 | * Returns 1 if found, with @key_tfm set | |
1720 | * Returns 0 if not found, with @key_tfm set to NULL | |
1721 | */ | |
1722 | int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm) | |
1723 | { | |
1724 | struct ecryptfs_key_tfm *tmp_key_tfm; | |
1725 | ||
1726 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); | |
1727 | ||
1728 | list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) { | |
1729 | if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) { | |
1730 | if (key_tfm) | |
1731 | (*key_tfm) = tmp_key_tfm; | |
1732 | return 1; | |
1733 | } | |
1734 | } | |
1735 | if (key_tfm) | |
1736 | (*key_tfm) = NULL; | |
1737 | return 0; | |
1738 | } | |
1739 | ||
1740 | /** | |
1741 | * ecryptfs_get_tfm_and_mutex_for_cipher_name | |
1742 | * | |
1743 | * @tfm: set to cached tfm found, or new tfm created | |
1744 | * @tfm_mutex: set to mutex for cached tfm found, or new tfm created | |
1745 | * @cipher_name: the name of the cipher to search for and/or add | |
1746 | * | |
1747 | * Sets pointers to @tfm & @tfm_mutex matching @cipher_name. | |
1748 | * Searches for cached item first, and creates new if not found. | |
1749 | * Returns 0 on success, non-zero if adding new cipher failed | |
1750 | */ | |
f4aad16a MH |
1751 | int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm, |
1752 | struct mutex **tfm_mutex, | |
1753 | char *cipher_name) | |
1754 | { | |
1755 | struct ecryptfs_key_tfm *key_tfm; | |
1756 | int rc = 0; | |
1757 | ||
1758 | (*tfm) = NULL; | |
1759 | (*tfm_mutex) = NULL; | |
af440f52 | 1760 | |
f4aad16a | 1761 | mutex_lock(&key_tfm_list_mutex); |
af440f52 ES |
1762 | if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) { |
1763 | rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); | |
1764 | if (rc) { | |
1765 | printk(KERN_ERR "Error adding new key_tfm to list; " | |
1766 | "rc = [%d]\n", rc); | |
f4aad16a MH |
1767 | goto out; |
1768 | } | |
1769 | } | |
f4aad16a MH |
1770 | (*tfm) = key_tfm->key_tfm; |
1771 | (*tfm_mutex) = &key_tfm->key_tfm_mutex; | |
1772 | out: | |
71fd5179 | 1773 | mutex_unlock(&key_tfm_list_mutex); |
f4aad16a MH |
1774 | return rc; |
1775 | } | |
51ca58dc MH |
1776 | |
1777 | /* 64 characters forming a 6-bit target field */ | |
1778 | static unsigned char *portable_filename_chars = ("-.0123456789ABCD" | |
1779 | "EFGHIJKLMNOPQRST" | |
1780 | "UVWXYZabcdefghij" | |
1781 | "klmnopqrstuvwxyz"); | |
1782 | ||
1783 | /* We could either offset on every reverse map or just pad some 0x00's | |
1784 | * at the front here */ | |
0f751e64 | 1785 | static const unsigned char filename_rev_map[256] = { |
51ca58dc MH |
1786 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */ |
1787 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */ | |
1788 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */ | |
1789 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */ | |
1790 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */ | |
1791 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */ | |
1792 | 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */ | |
1793 | 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */ | |
1794 | 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */ | |
1795 | 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */ | |
1796 | 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */ | |
1797 | 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */ | |
1798 | 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */ | |
1799 | 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */ | |
1800 | 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */ | |
0f751e64 | 1801 | 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */ |
51ca58dc MH |
1802 | }; |
1803 | ||
1804 | /** | |
1805 | * ecryptfs_encode_for_filename | |
1806 | * @dst: Destination location for encoded filename | |
1807 | * @dst_size: Size of the encoded filename in bytes | |
1808 | * @src: Source location for the filename to encode | |
1809 | * @src_size: Size of the source in bytes | |
1810 | */ | |
37028758 | 1811 | static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size, |
51ca58dc MH |
1812 | unsigned char *src, size_t src_size) |
1813 | { | |
1814 | size_t num_blocks; | |
1815 | size_t block_num = 0; | |
1816 | size_t dst_offset = 0; | |
1817 | unsigned char last_block[3]; | |
1818 | ||
1819 | if (src_size == 0) { | |
1820 | (*dst_size) = 0; | |
1821 | goto out; | |
1822 | } | |
1823 | num_blocks = (src_size / 3); | |
1824 | if ((src_size % 3) == 0) { | |
1825 | memcpy(last_block, (&src[src_size - 3]), 3); | |
1826 | } else { | |
1827 | num_blocks++; | |
1828 | last_block[2] = 0x00; | |
1829 | switch (src_size % 3) { | |
1830 | case 1: | |
1831 | last_block[0] = src[src_size - 1]; | |
1832 | last_block[1] = 0x00; | |
1833 | break; | |
1834 | case 2: | |
1835 | last_block[0] = src[src_size - 2]; | |
1836 | last_block[1] = src[src_size - 1]; | |
1837 | } | |
1838 | } | |
1839 | (*dst_size) = (num_blocks * 4); | |
1840 | if (!dst) | |
1841 | goto out; | |
1842 | while (block_num < num_blocks) { | |
1843 | unsigned char *src_block; | |
1844 | unsigned char dst_block[4]; | |
1845 | ||
1846 | if (block_num == (num_blocks - 1)) | |
1847 | src_block = last_block; | |
1848 | else | |
1849 | src_block = &src[block_num * 3]; | |
1850 | dst_block[0] = ((src_block[0] >> 2) & 0x3F); | |
1851 | dst_block[1] = (((src_block[0] << 4) & 0x30) | |
1852 | | ((src_block[1] >> 4) & 0x0F)); | |
1853 | dst_block[2] = (((src_block[1] << 2) & 0x3C) | |
1854 | | ((src_block[2] >> 6) & 0x03)); | |
1855 | dst_block[3] = (src_block[2] & 0x3F); | |
1856 | dst[dst_offset++] = portable_filename_chars[dst_block[0]]; | |
1857 | dst[dst_offset++] = portable_filename_chars[dst_block[1]]; | |
1858 | dst[dst_offset++] = portable_filename_chars[dst_block[2]]; | |
1859 | dst[dst_offset++] = portable_filename_chars[dst_block[3]]; | |
1860 | block_num++; | |
1861 | } | |
1862 | out: | |
1863 | return; | |
1864 | } | |
1865 | ||
4a26620d TH |
1866 | static size_t ecryptfs_max_decoded_size(size_t encoded_size) |
1867 | { | |
1868 | /* Not exact; conservatively long. Every block of 4 | |
1869 | * encoded characters decodes into a block of 3 | |
1870 | * decoded characters. This segment of code provides | |
1871 | * the caller with the maximum amount of allocated | |
1872 | * space that @dst will need to point to in a | |
1873 | * subsequent call. */ | |
1874 | return ((encoded_size + 1) * 3) / 4; | |
1875 | } | |
1876 | ||
71c11c37 MH |
1877 | /** |
1878 | * ecryptfs_decode_from_filename | |
1879 | * @dst: If NULL, this function only sets @dst_size and returns. If | |
1880 | * non-NULL, this function decodes the encoded octets in @src | |
1881 | * into the memory that @dst points to. | |
1882 | * @dst_size: Set to the size of the decoded string. | |
1883 | * @src: The encoded set of octets to decode. | |
1884 | * @src_size: The size of the encoded set of octets to decode. | |
1885 | */ | |
1886 | static void | |
1887 | ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size, | |
1888 | const unsigned char *src, size_t src_size) | |
51ca58dc MH |
1889 | { |
1890 | u8 current_bit_offset = 0; | |
1891 | size_t src_byte_offset = 0; | |
1892 | size_t dst_byte_offset = 0; | |
51ca58dc MH |
1893 | |
1894 | if (dst == NULL) { | |
4a26620d | 1895 | (*dst_size) = ecryptfs_max_decoded_size(src_size); |
51ca58dc MH |
1896 | goto out; |
1897 | } | |
1898 | while (src_byte_offset < src_size) { | |
1899 | unsigned char src_byte = | |
1900 | filename_rev_map[(int)src[src_byte_offset]]; | |
1901 | ||
1902 | switch (current_bit_offset) { | |
1903 | case 0: | |
1904 | dst[dst_byte_offset] = (src_byte << 2); | |
1905 | current_bit_offset = 6; | |
1906 | break; | |
1907 | case 6: | |
1908 | dst[dst_byte_offset++] |= (src_byte >> 4); | |
1909 | dst[dst_byte_offset] = ((src_byte & 0xF) | |
1910 | << 4); | |
1911 | current_bit_offset = 4; | |
1912 | break; | |
1913 | case 4: | |
1914 | dst[dst_byte_offset++] |= (src_byte >> 2); | |
1915 | dst[dst_byte_offset] = (src_byte << 6); | |
1916 | current_bit_offset = 2; | |
1917 | break; | |
1918 | case 2: | |
1919 | dst[dst_byte_offset++] |= (src_byte); | |
1920 | dst[dst_byte_offset] = 0; | |
1921 | current_bit_offset = 0; | |
1922 | break; | |
1923 | } | |
1924 | src_byte_offset++; | |
1925 | } | |
1926 | (*dst_size) = dst_byte_offset; | |
1927 | out: | |
71c11c37 | 1928 | return; |
51ca58dc MH |
1929 | } |
1930 | ||
1931 | /** | |
1932 | * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text | |
1933 | * @crypt_stat: The crypt_stat struct associated with the file anem to encode | |
1934 | * @name: The plaintext name | |
1935 | * @length: The length of the plaintext | |
1936 | * @encoded_name: The encypted name | |
1937 | * | |
1938 | * Encrypts and encodes a filename into something that constitutes a | |
1939 | * valid filename for a filesystem, with printable characters. | |
1940 | * | |
1941 | * We assume that we have a properly initialized crypto context, | |
1942 | * pointed to by crypt_stat->tfm. | |
1943 | * | |
1944 | * Returns zero on success; non-zero on otherwise | |
1945 | */ | |
1946 | int ecryptfs_encrypt_and_encode_filename( | |
1947 | char **encoded_name, | |
1948 | size_t *encoded_name_size, | |
1949 | struct ecryptfs_crypt_stat *crypt_stat, | |
1950 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat, | |
1951 | const char *name, size_t name_size) | |
1952 | { | |
1953 | size_t encoded_name_no_prefix_size; | |
1954 | int rc = 0; | |
1955 | ||
1956 | (*encoded_name) = NULL; | |
1957 | (*encoded_name_size) = 0; | |
1958 | if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES)) | |
1959 | || (mount_crypt_stat && (mount_crypt_stat->flags | |
1960 | & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) { | |
1961 | struct ecryptfs_filename *filename; | |
1962 | ||
1963 | filename = kzalloc(sizeof(*filename), GFP_KERNEL); | |
1964 | if (!filename) { | |
1965 | printk(KERN_ERR "%s: Out of memory whilst attempting " | |
a8f12864 | 1966 | "to kzalloc [%zd] bytes\n", __func__, |
51ca58dc MH |
1967 | sizeof(*filename)); |
1968 | rc = -ENOMEM; | |
1969 | goto out; | |
1970 | } | |
1971 | filename->filename = (char *)name; | |
1972 | filename->filename_size = name_size; | |
1973 | rc = ecryptfs_encrypt_filename(filename, crypt_stat, | |
1974 | mount_crypt_stat); | |
1975 | if (rc) { | |
1976 | printk(KERN_ERR "%s: Error attempting to encrypt " | |
1977 | "filename; rc = [%d]\n", __func__, rc); | |
1978 | kfree(filename); | |
1979 | goto out; | |
1980 | } | |
1981 | ecryptfs_encode_for_filename( | |
1982 | NULL, &encoded_name_no_prefix_size, | |
1983 | filename->encrypted_filename, | |
1984 | filename->encrypted_filename_size); | |
1985 | if ((crypt_stat && (crypt_stat->flags | |
1986 | & ECRYPTFS_ENCFN_USE_MOUNT_FNEK)) | |
1987 | || (mount_crypt_stat | |
1988 | && (mount_crypt_stat->flags | |
1989 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) | |
1990 | (*encoded_name_size) = | |
1991 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1992 | + encoded_name_no_prefix_size); | |
1993 | else | |
1994 | (*encoded_name_size) = | |
1995 | (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1996 | + encoded_name_no_prefix_size); | |
1997 | (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL); | |
1998 | if (!(*encoded_name)) { | |
1999 | printk(KERN_ERR "%s: Out of memory whilst attempting " | |
a8f12864 | 2000 | "to kzalloc [%zd] bytes\n", __func__, |
51ca58dc MH |
2001 | (*encoded_name_size)); |
2002 | rc = -ENOMEM; | |
2003 | kfree(filename->encrypted_filename); | |
2004 | kfree(filename); | |
2005 | goto out; | |
2006 | } | |
2007 | if ((crypt_stat && (crypt_stat->flags | |
2008 | & ECRYPTFS_ENCFN_USE_MOUNT_FNEK)) | |
2009 | || (mount_crypt_stat | |
2010 | && (mount_crypt_stat->flags | |
2011 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) { | |
2012 | memcpy((*encoded_name), | |
2013 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, | |
2014 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE); | |
2015 | ecryptfs_encode_for_filename( | |
2016 | ((*encoded_name) | |
2017 | + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE), | |
2018 | &encoded_name_no_prefix_size, | |
2019 | filename->encrypted_filename, | |
2020 | filename->encrypted_filename_size); | |
2021 | (*encoded_name_size) = | |
2022 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
2023 | + encoded_name_no_prefix_size); | |
2024 | (*encoded_name)[(*encoded_name_size)] = '\0'; | |
51ca58dc | 2025 | } else { |
df6ad33b | 2026 | rc = -EOPNOTSUPP; |
51ca58dc MH |
2027 | } |
2028 | if (rc) { | |
2029 | printk(KERN_ERR "%s: Error attempting to encode " | |
2030 | "encrypted filename; rc = [%d]\n", __func__, | |
2031 | rc); | |
2032 | kfree((*encoded_name)); | |
2033 | (*encoded_name) = NULL; | |
2034 | (*encoded_name_size) = 0; | |
2035 | } | |
2036 | kfree(filename->encrypted_filename); | |
2037 | kfree(filename); | |
2038 | } else { | |
2039 | rc = ecryptfs_copy_filename(encoded_name, | |
2040 | encoded_name_size, | |
2041 | name, name_size); | |
2042 | } | |
2043 | out: | |
2044 | return rc; | |
2045 | } | |
2046 | ||
2047 | /** | |
2048 | * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext | |
2049 | * @plaintext_name: The plaintext name | |
2050 | * @plaintext_name_size: The plaintext name size | |
2051 | * @ecryptfs_dir_dentry: eCryptfs directory dentry | |
2052 | * @name: The filename in cipher text | |
2053 | * @name_size: The cipher text name size | |
2054 | * | |
2055 | * Decrypts and decodes the filename. | |
2056 | * | |
2057 | * Returns zero on error; non-zero otherwise | |
2058 | */ | |
2059 | int ecryptfs_decode_and_decrypt_filename(char **plaintext_name, | |
2060 | size_t *plaintext_name_size, | |
0747fdb2 | 2061 | struct super_block *sb, |
51ca58dc MH |
2062 | const char *name, size_t name_size) |
2063 | { | |
2aac0cf8 | 2064 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
0747fdb2 | 2065 | &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
51ca58dc MH |
2066 | char *decoded_name; |
2067 | size_t decoded_name_size; | |
2068 | size_t packet_size; | |
2069 | int rc = 0; | |
2070 | ||
2aac0cf8 TH |
2071 | if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) |
2072 | && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
2073 | && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) | |
51ca58dc MH |
2074 | && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, |
2075 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) { | |
51ca58dc MH |
2076 | const char *orig_name = name; |
2077 | size_t orig_name_size = name_size; | |
2078 | ||
2079 | name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2080 | name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
71c11c37 MH |
2081 | ecryptfs_decode_from_filename(NULL, &decoded_name_size, |
2082 | name, name_size); | |
51ca58dc MH |
2083 | decoded_name = kmalloc(decoded_name_size, GFP_KERNEL); |
2084 | if (!decoded_name) { | |
2085 | printk(KERN_ERR "%s: Out of memory whilst attempting " | |
df261c52 | 2086 | "to kmalloc [%zd] bytes\n", __func__, |
51ca58dc MH |
2087 | decoded_name_size); |
2088 | rc = -ENOMEM; | |
2089 | goto out; | |
2090 | } | |
71c11c37 MH |
2091 | ecryptfs_decode_from_filename(decoded_name, &decoded_name_size, |
2092 | name, name_size); | |
51ca58dc MH |
2093 | rc = ecryptfs_parse_tag_70_packet(plaintext_name, |
2094 | plaintext_name_size, | |
2095 | &packet_size, | |
2096 | mount_crypt_stat, | |
2097 | decoded_name, | |
2098 | decoded_name_size); | |
2099 | if (rc) { | |
2100 | printk(KERN_INFO "%s: Could not parse tag 70 packet " | |
2101 | "from filename; copying through filename " | |
2102 | "as-is\n", __func__); | |
2103 | rc = ecryptfs_copy_filename(plaintext_name, | |
2104 | plaintext_name_size, | |
2105 | orig_name, orig_name_size); | |
2106 | goto out_free; | |
2107 | } | |
2108 | } else { | |
2109 | rc = ecryptfs_copy_filename(plaintext_name, | |
2110 | plaintext_name_size, | |
2111 | name, name_size); | |
2112 | goto out; | |
2113 | } | |
2114 | out_free: | |
2115 | kfree(decoded_name); | |
2116 | out: | |
2117 | return rc; | |
2118 | } | |
4a26620d TH |
2119 | |
2120 | #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143 | |
2121 | ||
2122 | int ecryptfs_set_f_namelen(long *namelen, long lower_namelen, | |
2123 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
2124 | { | |
2125 | struct blkcipher_desc desc; | |
2126 | struct mutex *tfm_mutex; | |
2127 | size_t cipher_blocksize; | |
2128 | int rc; | |
2129 | ||
2130 | if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { | |
2131 | (*namelen) = lower_namelen; | |
2132 | return 0; | |
2133 | } | |
2134 | ||
2135 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex, | |
2136 | mount_crypt_stat->global_default_fn_cipher_name); | |
2137 | if (unlikely(rc)) { | |
2138 | (*namelen) = 0; | |
2139 | return rc; | |
2140 | } | |
2141 | ||
2142 | mutex_lock(tfm_mutex); | |
2143 | cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm); | |
2144 | mutex_unlock(tfm_mutex); | |
2145 | ||
2146 | /* Return an exact amount for the common cases */ | |
2147 | if (lower_namelen == NAME_MAX | |
2148 | && (cipher_blocksize == 8 || cipher_blocksize == 16)) { | |
2149 | (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16; | |
2150 | return 0; | |
2151 | } | |
2152 | ||
2153 | /* Return a safe estimate for the uncommon cases */ | |
2154 | (*namelen) = lower_namelen; | |
2155 | (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2156 | /* Since this is the max decoded size, subtract 1 "decoded block" len */ | |
2157 | (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3; | |
2158 | (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE; | |
2159 | (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES; | |
2160 | /* Worst case is that the filename is padded nearly a full block size */ | |
2161 | (*namelen) -= cipher_blocksize - 1; | |
2162 | ||
2163 | if ((*namelen) < 0) | |
2164 | (*namelen) = 0; | |
2165 | ||
2166 | return 0; | |
2167 | } |